Steven Pinker, one of the world’s leading authorities on language and the mind and author of the books The Stuff of Thought, The Blank Slate, and How the Mind Works, discusses and signs his latest book, The Better Angels of Our Nature: Why Violence Has Declined. Pinker explores the essence of human nature, mixing psychology and history to provide a picture of an increasingly nonviolent world. The key, he argues, is to understand our intrinsic motives—the inner demons that incline us toward violence and the better angels that steer us away.